Re: Fresh Water Overflow Vent Project
Reply #3 –
Before you run another vent line or install an automatic vent,you might consider this. The only reason for vents for fixtures is to prevent siphoning the P trap dry which will allow sewer gas inside. They also are necessary for flush toilets in houses but that's another issue. The only way I see to fill the drain lines to a point that would allow sufficient negative pressure to siphon a trap would be if you had a bath tub, and, maybe, if you filled a sink completely full and then dumped it. Of course you could seal it again by running a few ounces of water to refill trap.
Since I do neither in the RV, the auto vents will be replaced with solid caps. Of course the black and grey tanks need to be vented but that's taken care of. I'm sick of these sewer gas emitters and am convinced they are unnecessary. We'll see....